In conventional parking brakes for vehicles, a hand or foot brake lever pivotally mounts to a frame of the vehicle or an intermediary parking brake actuator frame. A sheathed brake cable extends between an arm of the lever and a wheel brake of the vehicle. Pivotal movement of the brake lever from a brake-released position toward a brake-applied position tensions the brake cable, thereby engaging (i.e., activating) the wheel brake.
When a conventional parking brake is initially installed in a vehicle, slack in the brake cable can be removed to minimize the extent to which the brake lever pivots before causing the wheel brakes to engage. Removing or taking up the slack in the brake cable minimizes the wasted stroke length of the lever and maximizes the useful lever stroke that an operator uses to create the braking force.
As a parking brake is repeatedly used, the brake cable tends to stretch and/or its cable sheathing tends to compress. This can create slack in the brake cable system which reduces the useful stroke length of the brake lever. In some circumstances, the stretching of the cable and compression of the sheathing can be so severe that the wheel brake does not securely engage even when an operator moves the brake lever into a fully engaged position.
Various conventional parking brake actuators include self-adjusting mechanisms that automatically take up slack in the brake cable to minimize or eliminate the problems associated with brake cable stretching. These mechanisms use disengagement of the primary locking feature in the release position of the parking brake to allow the cable system to adjust in both directions. This disengagement requires a certain amount of cable travel and/or parking brake lever rotation to reapply the primary to lock the self-adjusting member. As such, lost cable travel occurs.
Some self-adjusting mechanisms may have a one-way locking mechanism, which includes a spring to constantly try to balance the system. However, when the parking brake is being returned from the brake-applied position to the break-released position, the equalizer of the rear cable system can become stuck or seized. If the equalizer does not move as the parking brake is released, slack can be created by the seized equalizer and will be taken up by the spring force. As a result, the parking brake will be in a brake-released position, but the rear cable system may still be applied.
Other conventional adjusting mechanisms are quite cumbersome to install and adjust. For example, the AL-KO quick adjuster (Part. No. 561711668) includes two racks that are clamped together to provide a two-way lock. However, it requires the original equipment manufacturer (OEM) to install the parking brake, loosen the bolt that clamps the two racks together, makes adjustments, and then retightened the bolt to a predetermined toque to lock.
Thus, an improved parking brake cable adjust system is desired.